Chainslingsaresuitableforheavyslenderarticles，suchas（）.
A. timberorsteelrails
B. locomotivesorboilers
C. railwaypassengercoaches
D. motorvehicles
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Whensteamisbeingraisedonaboiler,thewaterlevelwillnormally（）.
A. dropastheboilerwarmsup
B. riseastheboilerwarmsup
C. remainunchangeduntiltheboilerishotenough
D. riseandfallwiththesteamdemand
Cracksmaybepreventedfromdevelopingatthecornersofweldedplatinginsertsby（）.
A. squaringthecorners
B. roundingthecorners
C. plugweldingthecorners
D. slotweldingthecorners
Duringfueling，alldoors，hatches，andports（）.
A. towindwardshouldbeopenedandtheonestoleewardshouldbeclosed
B. toleewardshouldbeopenedandtheonestowindwardshouldbeclosed
C. shouldbeopened
D. shouldbeclosed
Thewaterlevelinasteamingauxiliaryboilerwillalways（）
A. risewhenthesteampressureisincreased
B. remainconstantaslongasthefeedpumpoperates
C. fallwhenthesteampressureisdecreased
D. varyasthesteamdemandchanges
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